WASHINGTON (AP) — House Republicans targeting Planned Parenthood released documents that they say may point to businesses profiting from the sale of fetal tissue for research. Democrats said the documents showed no direct evidence of profiteering.

The documents, released on Wednesday by a special House panel investigating fetal tissue donation by such groups as Planned Parenthood, include promotional and administrative materials that detail how some businesses procure fetal tissue from abortion providers and then sell them to researchers. Republicans on the panel would not reveal the source of the materials, saying they came from investigative work by staff.

The investigative panel was created last year following conservative furor over secretly recorded videos showing Planned Parenthood officials discussing how they sometimes supply fetal tissue for medical research. The documents were released in advance of a hearing that questioned whether the businesses that procure the tissue are violating a federal prohibition against profiting from those sales.

Republicans say the documents show that abortion clinics aren't incurring enough costs to make up for the profit of selling the parts to the procurement businesses. Tennessee Rep. Marsha Blackburn, chairwoman of the select committee, pointed to documents that show websites offering various body parts from babies, available by the gestation period of the pregnancy at the time of the abortion. She said the business has been growing in recent years.

"This sounds like someone who wants to make money, a lot of money selling baby body parts," Blackburn said at the hearing.

Democrats said the documents showed no direct evidence of those profits, and criticized Republicans for not calling the companies themselves to testify. Witnesses at the hearing included prosecutors and lawyers with no direct connection to the companies cited in the materials.

The Democrats reiterated their calls to end the investigation and shut down the select committee.

"This investigation has never been, and has no promise of becoming, fair or fact-based," said Rep. Jan Schakowsky of Illinois, the top Democrat on the panel.

Schakowsky referred to letters from one of the procurement companies, StemExpress, saying that the company has actually lost money on fetal tissue procurement. The company said some of the evidence in the documents released by the panel may have been obtained illegally by hackers and mischaracterizes the company's business, which also deals with adult blood and tissue.

Earlier this year, the committee issued several subpoenas to organizations, including StemExpress, which the panel said had been uncooperative. Democrats vehemently objected, saying that there are no rules in place to protect the names of those subpoenaed from public exposure.

Planned Parenthood has denied wrongdoing, and investigations by several states and congressional panels have not produced evidence that it acted illegally. Still, the undercover videos, which began appearing last July, have been cited by governors and legislators in numerous Republican-led states as justification for cutting off public funding for Planned Parenthood.

In a conference call with reporters Wednesday, Planned Parenthood president Cecile Richards said at least 24 states have taken such steps, although some of those efforts have been blocked by litigation.

Among those joining the call was Dr. Hal Lawrence, CEO of the American College of Obstetricians and Gynecologists. He said defunding of Planned Parenthood in states such as Florida and Texas would deprive many low-income women of access to such services as contraceptive counseling and screenings for cancer and sexually transmitted diseases.

He rejected claims from proponents of defunding that other providers could meet the demand for such services.

"That's simply impossible," Lawrence said. "Our health care system is not equipped to meet that level of need."